Synthetic mammalian sulphamidase and genetic sequences encoding same

ABSTRACT

The present invention relates generally to mammalian sulphamidase and to genetic sequences encoding same and to the use of these in the investigation, diagnosis and treatment of subjects suspected of or suffering from sulphamidase deficiency.

FIELD OF INVENTION

[0001] The present invention relates generally to mammalian sulphamidaseand to genetic sequences encoding same and to the use of these in theinvestigation, diagnosis and treatment of subjects suspected of orsuffering from sulphamidase deficiency.

[0002] Bibliographic details of the publications referred to by authorin this specification are collected at the end of the description.Sequence Identity Numbers (SEQ ID NOs.) for the nucleotide and aminoacid sequences referred to in the specification are defined followingthe bibliography.

[0003] Throughout this specification, unless the context requiresotherwise, the word “comprise”, or variations such as “comprises” or“comprising”, will be understood to imply the inclusion of a statedelement or Beer or group of elements or integers but not the exclusionof any other element or integer or group of elements or integers.

BACKGROUND TO THE INVENTION

[0004] The increasing sophistication of recombinant DNA technology isgreatly facilitating the efficacy of many commercially importantindustries including areas of medical and pharmaceutical research anddevelopment The ability to purify native proteins and subsequently clonegenetic sequences encoding these proteins is an important first step inthe development of a range of therapeutic and diagnostic procedures.However, practitioners have faced many difficulties in purifying targetmolecules to an extent sufficient to determine amino acid sequences topermit the development of oligonucleotide probes to assist in thecloning of genetic sequences encoding the target molecules.

[0005] Such difficulties have been particularly faced in the researchand development of lysosomal enzymes. An important lysosomal enzyme Issulphamidase (sulphamate sulphohydrolase EC 3.10.11). This enzyme actsas a exosulphatase in lysosomes to hydrolyse the sulphate ester bond in2-sulphaminoglucosamine residues present in heparan sulphate and heparin(Hopwood, 1989). A deficiency in this lysosomal hydrolase is responsiblefor the pathogenesis of Sanfilippo A Mucopolysaccharidosis type IIIA[MPS-IIIA3]) syndrome (Kresse, 1973; Matalon and Dorfman, 1974). This isan autosomal recessive disorder of glycosaminoglycan catabolism leadingto storage and excretion of excessive amounts of heparan sulphate and avariety of clinical phenotypes, but classically presenting withprogressive mental retardation in conjunction with skeletal deformities(McKusick and Neufeld, 1983).

[0006] There is a need, therefore, to purify sulphamidase and to clonegenetic sequences encoding same to permit development of a range oftherapeutic and diagnostic procedures to assist in the diagnosis andtreatment of disease conditions arising from sulphamidase deficiency.

SUMMARY OF THE INVENTION

[0007] One act of the invention provides an isolated nucleic acidmolecule comprising a sequence of nucleotides which encodes or iscomplementary to a sequence which encodes a mammalian sulphamidase orfragment or derivative thereof.

[0008] Another aspect of the invention is directed to an isolatednucleic acid molecule having a nucleotide sequence substantially as setforth in SEQ ID NO:1 or having at least 40% similarity to all or partthereof.

[0009] Yet another aspect of the present invention contemplates arecombinant mammalian sulphamidase or fragment or derivative thereof.

[0010] Still yet another aspect of the present invention provides anucleic acid molecule comprising a sequence of nucleotides encoding orcomplementary to a sequence encoding a polypeptide capable ofhydrolysing the sulphate ester bond in 2-sulphaminoglucosamine residuesand wherein said nucleotide sequence is capable of hybridising under lowstringency conditions to the nucleotide sequence set forth in FIG. 2(SEQ ID NO:1).

[0011] Still another aspect of the present invention is directed to apolypeptide comprising a sequence of amino acids corresponding to theamino sequence set forth in FIG. 2 (SEQ ID NO:2) or having at least 40%similarity thereto, more preferably at least 60% similarity thereto andstill more preferably at least 80% or 85-90% similarity thereto orencoded by the nucleotide sequence set forth in FIG. 2 (SEQ ID NO:1) ora nucleotide sequence capable of hybridising to SEQ ID NO:1 under low,preferably under medium and more preferably under high stringentconditions.

[0012] In still yet another aspect of the present invention there iscontemplated a method for treating a patient suffering from sulphamidasedeficiency said method comprising administering to said patient aneffective amount of recombinant mammalian sulphamidase or an activefragment or derivative thereof.

[0013] Another aspect of the present invention is directed to apharmaceutical composition comprising a recombinant mammaliansulphamidase or an active fragment or derivative thereof and one or morepharmaceutically acceptable carriers and/or diluents.

BRIEF DESCRIPTION OF THE FIGURES

[0014]FIG. 1 is a photographic representation of sulphamidase purifiedfrom liver, kidney and placenta following SDS/PAGE. Lane 1: M_(r)standards (kDa); Lanes 2, 3 and 5: Purified sulphamidase from humanliver, kidney and placenta, respectively; Lane 4: 16

[0015]FIG. 2 is a representation of the nucleotide sequence andcorresponding amino acid sequence in single letter code of humansulphamidase. * potential N-glycosylation site; ▾ probable site ofsignal peptide peptidase cleavage between amino acids 20 and 21.

[0016] The following single and three letter abbreviations arc used foramino acid residues: Three-letter One-letter Amino Acid AbbreviationSymbol Alanine Ala A Arginine Arg R Asparagine Asn N Aspartic acid Asp DCysteine Cys C Glutamine Gln Q Glutamic acid Glu E Glycine Gly GHistidine His H Isoleucine Ile I Leucine Leu L Lysine Lys K MethionineMet M Phenylalanine Phe F Proline Pro P Serine Ser S Threonine Thr TTryptophan Trp W Tyrosine Tyr Y Valine Val V Any residue Xaa X

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The present invention provides an isolated nucleic acid moleculecomprising a sequence of nucleotides which encodes, or are complementaryto a sequence which encodes, a mammalian sulphamidase or fragment orderivative thereof or its like molecule.

[0018] Preferably, the mammal is a human, livestock animal, companionanimal, wild animal or laboratory test animal (e.g. rabbit, rat, mouseor guinea pig). Most preferably, the mammal is a human. Conveniently,the sulphamidase is isolatable from the liver, kidney or placenta.However, the present invention extends to all mammalian sulphamidaseenzymes and from any anatomical or cellular source and/or any biologicalfluid source, such as but not limited to plasma, serum, cell extract orlymph fluid.

[0019] Although a preferred embodiment of the present inventioncontemplates the use of human sulphamidase or genomic or recombinant(e.g. cDNA) genetic sequences encoding same in the investigation,diagnosis and/or treatment of human subjects (i.e. homologous system),one skilled in the art will appreciate that the enzyme or geneticsequences encoding same from a non-human animal may also be useful. Sucha heterologous system is encompassed by the present invention.

[0020] The “nucleic acid molecule” of the present invention may be RNAor DNA (eg. cDNA), single or double stranded and linear or covalentlyclosed. The nucleic acid molecule may also be genomic DNA correspondingto the entire gene or a substantial portion thereof or to fragments andderivatives thereof. The nucleotide sequence may correspond to thenaturally occurring nucleotide sequence or may contain single ormultiple nucleotide substitutions, deletions and/or additions. All suchmodifications encode the sulphamidase-like molecules contemplated by thepresent invention. The length of the nucleotide sequence may vary from afew bases, such as in nucleic acid probes or primers, to a full lengthsequence.

[0021] The nucleic acid molecule of the present invention may constitutesolely the nucleotide sequence encoding sulphamidase or like molecule ormay be part of a larger nucleic acid molecule and extends to the genomicclone of sulphamidase. The non-sulphamidase encoding sequences in alarger nucleic acid molecule may include vector, promoter, terminator,enhancer, replication or signal sequences or non-coding regions of agenomic clone.

[0022] The present invention is particularly directed to the nucleicacid in cDNA form and particularly when inserted into an expressionvector. The expression vector may be replicable in a eukaryotic orprokaryotic cell and may either produce mRNA or the mRNA may besubsequently translated into sulphamidase or like molecule. Particularlypreferred eukaryotic cells include CHO cells but may be in any othersuitable mammalian cells or cell lines or non-mammalian cells such asyeast or insect cells.

[0023] The present invention is further directed to syntheticsulphamidase or like molecule. The term “synthetic” includes recombinantforms and molecules produced by the sequential addition of amino acidresidues, or groups of amino acid residues, in defined order. In a mostpreferred embodiment, the invention relates to recombinant sulphamidaseor like molecule encoded by or expressed from the nucleic acid moleculesas hereinbefore described.

[0024] The synthetic or recombinant sulphamidase may comprise an aminoacid sequence corresponding to the naturally occurring amino acidsequence or may contain single or multiple amino acid substitutions,deletions and/or additions. The length of the amino acid sequence mayrange from a few residues to a fill length molecule. Accordingly, thisaspect of the present invention contemplates a proteinaceous moleculecomprising an amino acid sequence corresponding to the fill lengthmammalian sulphamidase enzyme or to a like molecule. The like molecule,therefore, comprises parts, derivatives and/or portions of thesulphamidase enzyme whether functional or not. Preferably, the mammal ishuman but may be of non-human origin as contemplated above.

[0025] Advantageously, the recombinant sulphamidase is a biologicallypure preparation meaning that it has undergone some purification awayfor other proteins and/or non-proteinacous material. The purity of thepreparation may be represented as at least 40% of the enzyme, preferablyat least 6%, more preferably at least 75%, even more preferably at least85% and still more preferably at least 95% relative to non-sulphamidasematerial as determined by weight, activity, amino acid homology orsimilarity, antibody reactivity or other convenient means.

[0026] Amino acid insertional derivatives of sulphamidase of the presentinvention include amino and/or carboxyl terminal fusions as well asintra-sequence insertions of single or multiple amino acids. Insertionalamino acid sequence variants are those in which one or more amino acidresidues are introduced into a predetermined site in the proteinalthough random insertion is also possible with suitable screening ofthe resulting product. Deletional variants are characterised by theremoval of one or more amino acids from the sequence. Substitutionalamino acid variants are those in which at least one residue in thesequence has been removed and a different residue inserted in its place.Typical substitutions are those made in accordance with the followingTable 1: TABLE 1 Suitable residues for amino acid substitutions OriginalResidue Exemplary Substitutions Ala Ser Arg Lys Asn Gln; His Asp Glu CysSer Gln Asn Glu Asp Gly Pro His Asn; Gln Ile Leu; Val Leu Ile; Val LysArg; Gln; Glu Met Leu; Ile Phe Met; Leu; Tyr Ser Thr Thr Ser Trp Tyr TyrTrp; Phe Val Ile; Leu

[0027] Where the enzyme is derivatised by amino acid substitution, theamino acids arc generally replaced by other amino acids having likeproperties such as hydrophobicity, hydrophilicity, electronegativity,bully side chains and the like. Amino acid substitutions are typicallyof single residues. Amino acid insertions will usually be in the orderof about 1-10 amino acid residues and deletions will range from about1-20 residues. Preferably, deletions or insertions are made in adjacentpairs, i.e. a deletion of two residues or insertion of two residues.

[0028] The amino acid variants referred to above may readily be madeusing peptide synthetic techniques well known in the art, such as solidphase peptide synthesis (Merrifield synthesis) and the like, or byrecombinant DNA manipulations. Techniques for making substitutionmutations at predetermined sites in DNA having known or partially knownsequence are well known and include, for example, M13 mutagenesis. Themanipulation of DNA sequence to produce variant proteins which manifestas substitutional, insertional or deletional variants are convenientlyelsewhere described such as Sambrook et al, 1989 Molecular Cloning: ALaboratory Manual Cold Spring Harbor Laboratories, Cold Spring Harbor,N.Y.

[0029] The derivatives or like molecules include single or multiplesubstitutions, deletions and/or additions of any component(s) naturallyor artificially associated with the sulphamidase enzyme such ascarbohydrate, lipid and/or other proteinaceous moieties. For example,the present invention extends to glycosylated and non-glycosylated formsof the molecule. All such molecules are encompassed by the expression“mutants”, “derivatives, fragments”, “portions” and “like” molecules.These molecules may be active or non-active and may contain specificregions, such as a catalytic region. Particularly, preferred derivativemolecules include those with altered glycosylation patterns relative tothe naturally occurring molecule. Even more particularly, therecombinant molecule is more highly glycosylated to the naturallyoccurring molecule. Such higly glycosylated derivatives may haveimproved take-up proper s and enhanced half-lives.

[0030] The present invention also extends to synthetic sulphamidase orlike molecules when fused to other proteinaceous molecules. The lattermay include another enzyme, reporter molecule, purification site or anamino acid sequence which facilitates transport of the molecule out of acell, such as a signal sequence.

[0031] In a most preferred embodiment, the present invention has anamino acid or corresponding sulphamidase cDNA nucleotide sequencesubstantially as setforth in FIG. 2 having at least 40% similarity,preferably at least 60% similarity thereto or more preferably at least80% or 85-90% similarity thereto.

[0032] In a related embodiment, the present invention provides a nucleicacid molecule comprising a sequence of nucleotides encoding orcomplementary to a sequence encoding a polypeptide capable ofhydrolysing the sulphate ester bond in 2-sulphaminoglucosamine residuesand wherein said nucleotide sequence is capable of hybridising under lowstringency conditions to the nucleotide sequence set forth in FIG. 2(SEQ ID NO:1). Preferably, hybridisation is possible under mediumstringent conditions, more preferably, hybridisation is possible underhigh stringent conditions.

[0033] For the purposes of defining the level of stringency, referencecan conveniently be made to Maniatis et al (1982) at pages 387-389 whichis herein incorporated by reference where the washing steps disclosedare considered high stringency. A low stringency is defined herein asbeing in 4-6×SSC/0.1-0.5% w/v SDS at 37-45° C. for 2-3 hours. Dependingon the source and concentration of nucleic acid involved in thehybridisation, alternative conditions of stringency may be employed suchas medium stringent conditions which are considered herein to be1-4×SSC/0.25-0.5% w/v SDS at ≧45° C. for 2-3 hours or high stringentconditions considered herein to be 0.1-1×SSC/0.1% w/v SDS at 60° C. for1-3 hours.

[0034] In a further related embodiment, the present inventioncontemplates a polypeptide comprising a sequence of amino acidscorresponding to the amino sequence set forth in FIG. 2 (SEQ ID NO:2) orhaving at least 40% similarity thereto, more preferably at least 60%similarity thereto and still more preferably at least 80% or 85-90%similarity thereof or encoded by the nucleotide sequence set forth inFIG. 2 (SEQ ID NO:1) or a nucleotide sequence capable of hybridising toSEQ ID NO:1 under low, preferably under medium and more preferably underhigh stringent conditions.

[0035] The present invention extends to post-translational modificationsto the sulphamidase enzyme. The modifications may be made to thenaturally occurring enzyme or following synthesis by recombinanttechniques. The modifications may be at the structural level or at, forexample, the electrochemical level such as modifying net charge orstructural conformation of the enzyme.

[0036] Such modification may be important to facilitate entry orpenetration of the enzyme into selected tissues such as cartilage orblood brain barriers or to increase circulation half-life.

[0037] Such chemically or electrochemically modified ICAM-1-likepeptides are referred to herein as “analogues” and are included with theterm “derivatives”.

[0038] Analogues of sulphamidase contemplated herein include, but arenot limited to, modifications to side chains, incorporation of unnaturalamino acids and/or their derivatives during peptide synthesis and theuse of crosslinkers and other methods which impose conformationalconstraints on the enzyme.

[0039] Examples of side chain modifications contemplated by the presentinvention include modifications of amino groups such as by reductivealkylation by reaction with an aldehyde followed by reduction withNaBH₄; amidination with methylacetimidate; acylation with aceticanhydride; carbamoylation of amino groups with cyanate;trinitrobenzylation of amino groups with 2,4,6-trinitrobenzene sulphonicacid (TNBS); acylation of amino groups with succinic anhydride andtetrahydrophthalic anhydride; and pyridoxylation of lysine withpyridoxal-5′-phosphate followed by reduction with NaBH₄.

[0040] The guanidino group of arginine residues may be modified by theformation of heterocyclic condensation products with reagents such as2,3-butanedione, phenylglyoxal and glyoxal.

[0041] The carboxyl group may be modified by carbodiimide activation viaO-acylisourea formation followed by subsequent derivatisation, forexample, to a corresponding amide.

[0042] Sulphydryl groups may be modified by hods such ascarboxymethylation with iodoacetic acid or iodoacetamide; performic acidoxidation to cysteic acid; formation of a mixed disulphides with otherthiol compounds; reaction with maleimide, maleic anhydride or othersubstituted maleimide; formation of mercurial derivatives using4-chloromercuribenzoate, 4chloromercuriphenylsulphonic acid,phenylmercury chloride, 2-chloromercuric-4-nitrophenol and othermercurials; carbamoylation with cyanate at alkaline pH.

[0043] Tryptophan residues may be modified by, for example, oxidationwith N-bromosuccinimide or alkylation of the indole ring with2-hydroxy-5-nitrobenzyl bromide or sulphenyl halides. Tyrosine residueson the other hand, may be altered by nitration with tetranitromethane toform a 3-nitrotyrosine derivative.

[0044] Modification of the imidazole ring of a histidine residue may beaccomplished by alkylation with iodoacetic acid derivatives orN-carbethoxylation with diethylpyrocarbonate.

[0045] Examples of incorporating unnatural amino acids and derivativesduring peptide synthesis include, but arc not limited to, use ofnorleucine, 4-amino butyric acid, 4-amino-3-hydroxy-5-phenylpentanoicacid, 6-aminohexanoic acid, t-butylglycine, norvaline, phenylglycine,ornithine, sarcosine, 4-amino-3-hydroxy-6-methylheptanoic acid,2-thienyl alanine and/or D-isomers of amino acids.

[0046] Crosslinkers can be used, for example, to stabilise 3Dconformation, using homo-bifunctional crosslinkers such as thebifunctional imido esters having (CH₂)_(n) spacer groups with n=1 ton=6, glutaraldehyde, N-hydroxysuccinimide esters and hetero-bifunctionalreagents which usually contain an amino-reactive moiety such asN-hydroxysuccinimide and another group specific-reactive moiety such asmaleimido or dithio moiety (SH) or carbodiimide (COOH). In addition, then could be conformationally constrained by, for example, incorporationof C_(α) and N_(α)-methylamino acids, introduction of double bondsbetween C_(α) and C_(β) atoms of amino acids and the formation of cyclicpeptides or analogues by introducing covalent bonds such as forming anamide bond between the N and C termini, between two side chains orbetween a side chain and the N or C terminus.

[0047] Electrochemical modifications of sulphamidase include interactionwith polylysine or polyethylene glycol or other agent which effects anoverall change to the net charge of the enzyme.

[0048] The present invention further contemplates antibodies tosulphamidase and preferably synthetic sulphamidase or like molecule. Theantibodies may be polyclonal or monoclonal, naturally occurring orsynthetic (including recombinant, fragment or fusion forms). Suchantibodies will be useful in developing immunoassays for sulphamidase.

[0049] A further aspect of the present invention contemplates a methodof screening for abberations in the sulphamidase gene. Such a method maybe accomplished in a number of ways including isolating a source of DNAto be tested or mRNA therefrom and hybridising thereto a nucleic acidmolecule as hereinbefore described. Generally, the nucleic acid is probeor primer size and polymerase chain reaction is a convenient means bywhich to analyse the RNA or DNA. Other suitable assays include theligation chain reaction and the strand displacement amplificationmethods. The sulphamidase sequence can also be determined and comparedto the naturally occurring sequence. Such methods may be useful inadults and children and may be adapted for a pre-natal test. The DNA tobe tested includes a genomic sample crying the sulphamidase gene, a cDNAclone and/or amplification product.

[0050] In accordance with this aspect of the present invention there isprovided a method for screening for abberations in the sulphamidase geneincluding the absence of such a gene or a portion or a substantialportion thereof comprising isolating a sample of DNA or mRNAcorresponding to a region of said DNA and contacting same with anoligonucleotide probe capable of hybridising to one or morecomplementary sequences within the sulphamidase gene and then detectingthe hybridisation, the extent of hybridisation or the absence ofhybridisation. Alternatively, the probe is a primer and capable ofdirecting amplification of one or more regions of said sulphamidase geneand the amplification products and/or profile of amplification productsis compared to an individual carrying the fill gene or to a referencedate base. Conveniently, the amplification products are sequenced todetermine the presence or absence of the full gene.

[0051] The present invention Or extends to a method of treating patientssuffering from sulphamidase deficiency, such as in MPS-IIIA, said methodcomprising administering to said patient an effective amount ofsulphamidase or active like form thereof. Preferably, the sulphamidaseis in recombinant form. Such a method is referred to as “enzymetherapy”. Alternatively, gene therapy cam be employed includingintroducing an active gene (i.e. a nucleic acid molecule as hereinbeforedescribed) or to parts of the gene or other sequences which facilitateexpression of a naturally occurring sulphamidase gene.

[0052] Administration of the sulphamidase for enzyme therapy may be byoral, intravenous, suppository, intraperitoneal, intramuscular,intranasal, intradermal or subcutaneous administration or by infusion orimplantation. The sulphamidase is preferably as hereinbefore describedincluding active mutants or derivatives thereof and glycosylationvariants thereof. Administration may also be by way of gene therapyincluding expression of the gene by inclusion of the gene in viralvectors which are introduced into the animal (e.g. human) host to betreated. Alternatively, the gene may be expressed in a bacterial hostwhich is then introduced and becomes part of the bacterial flora in theanimal to be tested.

[0053] Still yet another aspect of the present invention is directed toa pharmaceutical composition comprising synthetic (e.g. recombinant)sulphamidase or like molecule, including active derivatives andfragments thereof, alone or in combination with other active molecules.Such other molecules may act synergistically with the enzyme orfacilitates its entry to a target cell. The composition will alsocontain one or more pharmaceutically acceptable carriers and/ordiluents. The composition may alternatively comprise a genetic componentuseful in gene therapy.

[0054] The active ingredients of the pharmaceutical compositioncomprising the synthetic or recombinant sulphamidase or mutants orfragments or derivatives thereof are contemplated to exhibit excellentactivity in treating patients with a deficiency in the enzyme whenadministered in an amount which depends on the particular case. Thevariation depends, for example, on the patient and the sulphamidaseused. For example, from about 0.5 μg to about 20 mg of enzyme per animalbody or, depending on the animal and other factors, per kilogram of bodyweight may be administered. Dosage regima may be adjusted to provide theoptimum therapeutic response. For example, several divided doses may beadministered daily, weekly, monthly or in other suitable time intervalsor the dose may be proportionally reduced as indicated by the exigenciesof the situation. Accordingly, alternative dosages in the order of 1.0μg to 15 mg, 2.0 μg to 10 mg or 10 μg to 5 mg may be administered in asingle or as part of multiple doses. The active compound may beadministered in a convenient manner such as by the oral, intravenous(where water soluble), intramuscular, subcutaneous, intranasal,intradermal or suppository routes or implanting (eg using slow releasemolecules). Depending on the route of administration, the activeingredients which comprise a synthetic (e.g. recombinant) sulphamidaseor fragments, derivatives or mutants thereof may be required to becoated in a material to protect same from the action of enzymes, acidsand other natural conditions which may inactivate said ingredients. Forexample, the low lipophilicity of sulphamidase will allow it to bedestroyed in the gastrointestinal tract by enzymes capable of cleavingpeptide bonds and in the stomach by acid hydrolysis. In order toadminister the vaccine by other than parenteral administration, theenzyme will be coated by, or administered with, a material to preventits inactivation. For example, the enzyme may be administered in anadjuvant, co-administered with enzyme inhibitors or in liposomes.Adjuvant is used id its broadest sense and includes any immunestimulating compound such as interferon. Adjuvants contemplated hereininclude resorcinols, non-ionic surfactants such as polyoxyethylene oleylether and n-hexadecyl polyethylene ether. Conveniently, the adjuvant isFreund's Complete or Incomplete Adjuvant. Enzyme inhibitors includepancreatic trypsin inhibitor, diisopropylfluorophosphate (DEP) andtrasylol. Liposomes include water-in-oil-in-water emulsions as well asconventional liposomes.

[0055] The active compound may also be administered in dispersionsprepared in glycerol, liquid polyethylene glycols, and/or mixturesthereof and in oils. Under ordinary conditions of storage and use, thesepreparations contain a preservative to prevent the growth ofmicroorganisms.

[0056] The pharmaceutical forms suitable for injectable use includesterile aqueous solutions (where rarer soluble) or dispersions andsterile powders for the extemporaneous preparation of sterile injectablesolutions or dispersion. In all cases the form must be sterile and mustbe fluid to the extent that easy syringability exists. It must be stableunder the conditions of manufacture and storage and must be preservedagainst the contaminating action of microorganisms such as bacteria andfungi. The carrier can be a solvent or dispersion medium containing, forexample, water, ethanol polyol (for example, glycerol, propylene glycol,and liquid polyethylene glycol, and the like), suitable mixturesthereof, and vegetable oils The proper fluidity can be maintained, forexample, by the use of a coating such as lecithin, by the maintenance ofthe required particle size in the case of dispersion and by the use ofsuperfactants. The prevention of the action of microorganisms Can bebrought about by various antibacterial and antifungal agents, forexample, parabens, chlorobutanol, phenol, sorbic acid, thirmerosal, andthe like. In many cases, it will be preferable to include isotonicagents, for example, sugars or sodium chloride. Prolonged absorption ofthe injectable compositions can be brought about by the Ad in thecompositions of agents delaying absorption, for example, aluminummonostearate and gelatin.

[0057] Sterile injectable solutions are prepared by incorporating theactive compound in the required amount in the appropriate solvent withvarious of the other ingredients enumerated above, as required, followedby filtered sterilization. Generally, dispersions are prepared byincorporating the various sterilized active ingredient(s) into a sterilevehicle which contains the basic dispersion medium and the requiredother ingredients from those enumerated above. In the case of sterilepowders for the preparation of sterile injectable solutions, thepreferred methods of preparation are vacuum drying and the freeze-dryingtechnique which yield a powder of the active ingredient plus anyadditional desired ingredient from previously sterile-filtered solutionthereof.

[0058] When the sulphamidase of the present invention is suitablyprotected as described above, the composition may be orallyadministered, for example, with an inert diluent or with an assimilableedible earner, or it may be enclosed in hard or soft shell gelatincapsule, or it may be compressed into tablets, or it may be incorporateddirectly with the food of the diet. For oral therapeutic administration,the active compound may be incorporated with excipients and used in theform of ingestible tablets, buccal tablet, troches, capsules, elixirs,suspensions, syrups, wafers, and the like. Such compositions andpreparations should contain at least 1% by weight of active compound.The percentage of the compositions and preparations may, of course, bevaried and may conveniently be between about 5 to about 80% of theweight of the unit. The amount of active compound in the vaccinecompositions is such that a suitable dosage will be obtained. Preferredcompositions or preparations according to the present invention areprepared, so that an oral dosage unit form contains between about 0.5 μgand 20 mg of active compound.

[0059] The tablets, troches, pills, capsules and the like may alsocontain the following: a binder such as gum gragacanth, acacia, cornstarch or gelatin; excipients such as dicalcium phosphate; adisintegrating agent such as corn starch, potato starch, alginic acidand the like; a lubricant such as magnesium sterate; and a sweeteningagent such a sucrose, lactose or saccharin may be added or a flavoringagent such as peppermint, oil of wintergreen, or cherry flavouring. Whenthe dosage unit form is a capsule, it may contain, in addition tomaterials of the above type, a liquid carrier. Various other materialsmay be present as coatings or to otherwise modify the physical form ofthe dosage unit. For instance, tablets, pills, or capsules may be coatedwith shellac, sugar or both. A syrup or elixir may contain the activecompound, sucrose as a sweetening agent, methyl and propylparabens aspreservatives, a dye and flavoring such as cherry or orange flavor. Ofcourse, any material used in preparing any dosage unit form should bepharmaceutically pure and substantially non-toxic in the amountsemployed. In addition, the active compound may be incorporated intosustained-release reparations and formulations.

[0060] As used herein “pharmaceutically acceptable carriers and/ordiluents” include any and all solvents, dispersion media, aqueoussolution; coatings, antibacterial and antifungal agents, isotonic andabsorption delaying agent and the like. The use of such media and agentsfor pharmaceutical active substances is well known in the art. Exceptinsofar as any conventional media or agent is incompatible with theactive ingredient, use thereof in the pharmaceutical compositions iscontemplated. Supplementary active ingredients can also be incorporatedinto the compositions.

[0061] The present invention further relates to the use of sulphamidaseor active fragment, mutant or derivative thereof in the manufacture of amedicament for the treatment of patients suffering from a deficiency inthe naturally occurring enzyme (e.g. MPS-IIIA).

[0062] The present invention is further described with reference to thefollowing non-limiting examples.

EXAMPLE 1 Purification of Sulphamidase

[0063] Sulphamidases were purified according to the method described inFreeman and Hopwood (1986). Enzymes were purified to homogenicity fromhuman liver, kidney and placenta. Evidence of purity is shown followingSDS/PAGE which is represented in FIG. 1. All samples were reduced withdithiothreitol prior to electrophoresis.

EXAMPLE 2 Characterisation of Sulphamidase

[0064] Results presented in FIG. 1 show a subunit of about M_(r) 56,000from sulphamidase purified from human liver, kidney and placenta Thenative M_(r) is about 100,000 to 120,000.

EXAMPLE 3 N-Terminal Amino Acid Sequence Determination

[0065] The N-terminal amino acid sequence was determined using themethods of Clements et al (1989) and Wilson et al (1990).

[0066] The amino acid sequence is shown in Table 2.

EXAMPLE 4 Cloning of Sulphamidase cDNA

[0067] The N-terminal amino acid sequence (Example 3) was used togenerate oligonucleotides and primers to screen a human kidney cDNAlibrary. An approximately 2.7 kbp cDNA clone was then isolated encodingthe entire sequence of human sulphamidase. The nucleotide sequence (SEQID NO:1) and corresponding amino acid sequence (SEQ ID NO:2) are shownin FIG. 2.

[0068] The amino acid sequence is shown in single letter code above thecDNA sequence. Nucleotide and amino acid numbers are in the rightmargin. The probable site of signal peptide peptidase cleavage betweenamino acids 20 and 21 is shown by an arrow. Amino acids colinear withthe amino-terminal peptide data is underlined. The five potentialN-glycosylation sites are asterisked above the peptide sequence. Theopen reading frame is 1506 nucleotides long and encodes a 502 amino acidprotein. The predicted molecular mass of the mature protein (minus the20 amino acid signal peptide) is about 54,679 kilo daltons. TABLE 2N-Terminal amino acid sequence (SEQ ID NO:3) determined from purifiedhuman liver sulphamidase R P R N A L L L L A D D G G F E S G A Y X¹ N SA I

[0069] Those skilled in the art will appreciate that the inventiondescribed herein is susceptible to variations and modifications otherMan those specifically described. It is to be understood that theinvention includes all such variations and modifications. The inventionalso includes all of the steps, features, compositions and compoundsreferred to or indicated in this specification, individually orcollectively, and any and all combinations of any two or more of saidsteps or features.

REFERENCES

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[0075] McKusick V and Neufeld E (1983) In: The Metabolic Basis ofInherited Disease” (Stanbury J B, Wyngaarden J B, Fredrickson D S,Goldstein J L and Brown M S, eds), 5th Ed., 751-771, McGraw-Hill NewYork.

[0076] Wilson P J, Morris C P, Anson D S, Occhiodoro T, Bielicki J,Clements P R and Hopwood J J (1990) Proc. Natl. Acad. Sci. USA 87:8531-8535.

1 3 2657 base pairs nucleic acid single linear DNA not provided CDS13..1518 1 GAATTCCGGG CC ATG AGC TGC CCC GTG CCC GCC TGC TGC GCG CTG CTG48 Met Ser Cys Pro Val Pro Ala Cys Cys Ala Leu Leu 1 5 10 CTA GTC CTGGGG CTC TGC CGG GCG CGT CCC CGG AAC GCA CTG CTG CTC 96 Leu Val Leu GlyLeu Cys Arg Ala Arg Pro Arg Asn Ala Leu Leu Leu 15 20 25 CTC GCG GAT GACGGA GGC TTT GAG AGT GGC GCG TAC AAC AAC AGC GCC 144 Leu Ala Asp Asp GlyGly Phe Glu Ser Gly Ala Tyr Asn Asn Ser Ala 30 35 40 ATC GCC ACC CCG CACCTG GAC GCC TTG GCC CGC CGC AGC CTC CTC TTT 192 Ile Ala Thr Pro His LeuAsp Ala Leu Ala Arg Arg Ser Leu Leu Phe 45 50 55 60 CGC AAT GCC TTC ACCTCG GTC AGC AGC TGC TCT CCC AGC CGC GCC AGC 240 Arg Asn Ala Phe Thr SerVal Ser Ser Cys Ser Pro Ser Arg Ala Ser 65 70 75 CTC CTC ACT GGC CTG CCCCAG CAT CAG AAT GGG ATG TAC GGG CTG CAC 288 Leu Leu Thr Gly Leu Pro GlnHis Gln Asn Gly Met Tyr Gly Leu His 80 85 90 CAG GAC GTG CAC CAC TTC AACTCC TTC GAC AAG GTG CGG AGC CTG CCG 336 Gln Asp Val His His Phe Asn SerPhe Asp Lys Val Arg Ser Leu Pro 95 100 105 CTG CTG CTC AGC CAA GCT GGTGTG CGC ACA GGC ATC ATC GGG AAG AAG 384 Leu Leu Leu Ser Gln Ala Gly ValArg Thr Gly Ile Ile Gly Lys Lys 110 115 120 CAC GTG GGG CCG GAG ACC GTGTAC CCG TTT GAC TTT GCG TAC ACG GAG 432 His Val Gly Pro Glu Thr Val TyrPro Phe Asp Phe Ala Tyr Thr Glu 125 130 135 140 GAG AAT GGC TCC GTC CTCCAG GTG GGG CGG AAC ATC ACT AGA ATT AAG 480 Glu Asn Gly Ser Val Leu GlnVal Gly Arg Asn Ile Thr Arg Ile Lys 145 150 155 CTG CTC GTC CGG AAA TTCCTG CAG ACT CAG GAT GAC CGG CCT TTC TTC 528 Leu Leu Val Arg Lys Phe LeuGln Thr Gln Asp Asp Arg Pro Phe Phe 160 165 170 CTC TAC GTC GCC TTC CACGAC CCC CAC CGC TGT GGG CAC TCC CAG CCC 576 Leu Tyr Val Ala Phe His AspPro His Arg Cys Gly His Ser Gln Pro 175 180 185 CAG TAC GGA ACC TTC TGTGAG AAG TTT GGC AAC GGA GAG AGC GGC ATG 624 Gln Tyr Gly Thr Phe Cys GluLys Phe Gly Asn Gly Glu Ser Gly Met 190 195 200 GGT CGT ATC CCA GAC TGGACC CCC CAG GCC TAC GAC CCA CTG GAC GTG 672 Gly Arg Ile Pro Asp Trp ThrPro Gln Ala Tyr Asp Pro Leu Asp Val 205 210 215 220 CTG GTG CCT TAC TTCGTC CCC AAC ACC CCG GCA GCC CGA GCC GAC CTG 720 Leu Val Pro Tyr Phe ValPro Asn Thr Pro Ala Ala Arg Ala Asp Leu 225 230 235 GCC GCT CAG TAC ACCACC GTC GGC CGC ATG GAC CAA GGA GTT GGA CTG 768 Ala Ala Gln Tyr Thr ThrVal Gly Arg Met Asp Gln Gly Val Gly Leu 240 245 250 GTG CTC CAG GAG CTGCGT GAC GCC GGT GTC CTG AAC GAC ACA CTG GTG 816 Val Leu Gln Glu Leu ArgAsp Ala Gly Val Leu Asn Asp Thr Leu Val 255 260 265 ATC TTC ACG TCC GACAAC GGG ATC CCC TTC CCC AGC GGC AGG ACC AAC 864 Ile Phe Thr Ser Asp AsnGly Ile Pro Phe Pro Ser Gly Arg Thr Asn 270 275 280 CTG TAC TGG CCG GGCACT GCT GAA CCC TTA CTG GTG TCA TCC CCG GAG 912 Leu Tyr Trp Pro Gly ThrAla Glu Pro Leu Leu Val Ser Ser Pro Glu 285 290 295 300 CAC CCA AAA CGCTGG GGC CAA GTC AGC GAG GCC TAC GTG AGC CTC CTA 960 His Pro Lys Arg TrpGly Gln Val Ser Glu Ala Tyr Val Ser Leu Leu 305 310 315 GAC CTC ACG CCCACC ATC TTG GAT TGG TTC TCG ATC CCG TAC CCC AGC 1008 Asp Leu Thr Pro ThrIle Leu Asp Trp Phe Ser Ile Pro Tyr Pro Ser 320 325 330 TAC GCC ATC TTTGGC TCG AAG ACC ATC CAC CTC ACT GGC CGG TCC CTC 1056 Tyr Ala Ile Phe GlySer Lys Thr Ile His Leu Thr Gly Arg Ser Leu 335 340 345 CTG CCG GCG CTGGAG GCC GAG CCC CTC TGG GCC ACC GTC TTT GGC AGC 1104 Leu Pro Ala Leu GluAla Glu Pro Leu Trp Ala Thr Val Phe Gly Ser 350 355 360 CAG AGC CAC CACGAG GTC ACC ATG TCC TAC CCC ATG CGC TCC GTG CAG 1152 Gln Ser His His GluVal Thr Met Ser Tyr Pro Met Arg Ser Val Gln 365 370 375 380 CAC CGG CACTTC CGC CTC GTG CAC AAC CTC AAC TTC AAG ATG CCC TTT 1200 His Arg His PheArg Leu Val His Asn Leu Asn Phe Lys Met Pro Phe 385 390 395 CCC ATC GACCAG GAC TTC TAC GTC TCA CCC ACC TTC CAG GAC CTC CTG 1248 Pro Ile Asp GlnAsp Phe Tyr Val Ser Pro Thr Phe Gln Asp Leu Leu 400 405 410 AAC CGC ACCACA GCT GGT CAG CCC ACG GGC TGG TAC AAG GAC CTC CGT 1296 Asn Arg Thr ThrAla Gly Gln Pro Thr Gly Trp Tyr Lys Asp Leu Arg 415 420 425 CAT TAC TACTAC CGG GCG CGC TGG GAG CTC TAC GAC CGG AGC CGG GAC 1344 His Tyr Tyr TyrArg Ala Arg Trp Glu Leu Tyr Asp Arg Ser Arg Asp 430 435 440 CCC CAC GAGACC CAG AAC CTG GCC ACC GAC CCG CGC TTT GCT CAG CTT 1392 Pro His Glu ThrGln Asn Leu Ala Thr Asp Pro Arg Phe Ala Gln Leu 445 450 455 460 CTG GAGATG CTT CGG GAC CAG CTG GCC AAG TGG CAG TGG GAG ACC CAC 1440 Leu Glu MetLeu Arg Asp Gln Leu Ala Lys Trp Gln Trp Glu Thr His 465 470 475 GAC CCCTGG GTG TGC GCC CCC GAC GGC GTC CTG GAG GAG AAG CTC TCT 1488 Asp Pro TrpVal Cys Ala Pro Asp Gly Val Leu Glu Glu Lys Leu Ser 480 485 490 CCC CAGTGC CAG CCC CTC CAC AAT GAG CTG TGACCATCCC AGGAGGCCTG 1538 Pro Gln CysGln Pro Leu His Asn Glu Leu 495 500 TGCACACATC CCAGGCATGT CCCAGACACATCCCACACGT GTCCGTGTGG CCGGCCAGCC 1598 TGGGGAGTAG TGGCAACAGC CCTTCCGTCCACACTCCCAT CCAAGGAGGG TTCTTCCTTC 1658 CTGTGGGGTC ACTCTTGCCA TTGCCTGGAGGGGGACCAGA GCATGTGACC AGAGCATGTG 1718 CCCAGCCCCT CCACCACCAG GGGCACTGCCGTCATGGCAG GGGACACAGT TGTCCTTGTG 1778 TCTGAACCAT GTCCCAGCAC GGGAATTCTAGACATACGTG GTCTGCGGAC AGGGCAGCGC 1838 CCCCAGCCCA TGACAAGGGA GTCTTGTTTTCTGGCTTGGT TTGGGGACCT GCAAATGGGA 1898 GGCCTGAGGC CCTCTTCAGG CTTTGGCAGCCACAGATACT TCTGAACCCT TCACAGAGAG 1958 CAGGCAGGGG CTTCGGTGCC GCGTGGGCAGTACGCAGGTC CCACCGACAC TCACCTGGGA 2018 GCACGGCGCC TGGCTCTTAC CAGCGTCTGGCCTAGAGGAA GCCTTTGAGC GACCTTTGGG 2078 CAGGTTTCTG CTTCTTCTGT TTTGCCCATGGTCAAGTCCC TGTTCCCCAG GCAGGTTTCA 2138 GCTGATTGGC AGCAGGCTCC CTGAGTGATGAGCTTGAACC TGTGGTGTTT CTGGGCAGAA 2198 GCTTATCTTT TTTGAGAGTG TCCGAAGATGAAGGCATGGC GATGCCCGTC CTCTGGCTTG 2258 GGTTAATTCT TCGGTGACAC TGGCATTGCTGGGTGGTGAT GCCCGTCCTC TGGCTTGGGT 2318 TAATTCTTCG GTGACACTGG CGTTGCTGGGTGGCAATGCC CGTCCTCTGG CTTGGGTTAA 2378 TTCTTCGGTG ACACTGGCGT TGCTGGGTGGCGATGCCCGT CCTCTGGCTT GGGTTAATTC 2438 TTGGATGACG TCGGCGTTGC TGGGAGAATGTGCCGTTCCT GCCCTGCCTC CACCCACCTC 2498 GGGAGCAGAA GCCCGGCCTG GACACCCCTCGGCCTGGACA CCCCTCGAAG GAGAGGGCGC 2558 TTCCTTGAGT AGGTGGGCTC CCCTTGCCCTTCCCTCCCTA TCACTCCATA CTGGGGTGGG 2618 CTGGAGGAGG CCACAGGCCA GCTATTGTAAAAGCTTTTT 2657 502 amino acids amino acid linear protein not provided 2Met Ser Cys Pro Val Pro Ala Cys Cys Ala Leu Leu Leu Val Leu Gly 1 5 1015 Leu Cys Arg Ala Arg Pro Arg Asn Ala Leu Leu Leu Leu Ala Asp Asp 20 2530 Gly Gly Phe Glu Ser Gly Ala Tyr Asn Asn Ser Ala Ile Ala Thr Pro 35 4045 His Leu Asp Ala Leu Ala Arg Arg Ser Leu Leu Phe Arg Asn Ala Phe 50 5560 Thr Ser Val Ser Ser Cys Ser Pro Ser Arg Ala Ser Leu Leu Thr Gly 65 7075 80 Leu Pro Gln His Gln Asn Gly Met Tyr Gly Leu His Gln Asp Val His 8590 95 His Phe Asn Ser Phe Asp Lys Val Arg Ser Leu Pro Leu Leu Leu Ser100 105 110 Gln Ala Gly Val Arg Thr Gly Ile Ile Gly Lys Lys His Val GlyPro 115 120 125 Glu Thr Val Tyr Pro Phe Asp Phe Ala Tyr Thr Glu Glu AsnGly Ser 130 135 140 Val Leu Gln Val Gly Arg Asn Ile Thr Arg Ile Lys LeuLeu Val Arg 145 150 155 160 Lys Phe Leu Gln Thr Gln Asp Asp Arg Pro PhePhe Leu Tyr Val Ala 165 170 175 Phe His Asp Pro His Arg Cys Gly His SerGln Pro Gln Tyr Gly Thr 180 185 190 Phe Cys Glu Lys Phe Gly Asn Gly GluSer Gly Met Gly Arg Ile Pro 195 200 205 Asp Trp Thr Pro Gln Ala Tyr AspPro Leu Asp Val Leu Val Pro Tyr 210 215 220 Phe Val Pro Asn Thr Pro AlaAla Arg Ala Asp Leu Ala Ala Gln Tyr 225 230 235 240 Thr Thr Val Gly ArgMet Asp Gln Gly Val Gly Leu Val Leu Gln Glu 245 250 255 Leu Arg Asp AlaGly Val Leu Asn Asp Thr Leu Val Ile Phe Thr Ser 260 265 270 Asp Asn GlyIle Pro Phe Pro Ser Gly Arg Thr Asn Leu Tyr Trp Pro 275 280 285 Gly ThrAla Glu Pro Leu Leu Val Ser Ser Pro Glu His Pro Lys Arg 290 295 300 TrpGly Gln Val Ser Glu Ala Tyr Val Ser Leu Leu Asp Leu Thr Pro 305 310 315320 Thr Ile Leu Asp Trp Phe Ser Ile Pro Tyr Pro Ser Tyr Ala Ile Phe 325330 335 Gly Ser Lys Thr Ile His Leu Thr Gly Arg Ser Leu Leu Pro Ala Leu340 345 350 Glu Ala Glu Pro Leu Trp Ala Thr Val Phe Gly Ser Gln Ser HisHis 355 360 365 Glu Val Thr Met Ser Tyr Pro Met Arg Ser Val Gln His ArgHis Phe 370 375 380 Arg Leu Val His Asn Leu Asn Phe Lys Met Pro Phe ProIle Asp Gln 385 390 395 400 Asp Phe Tyr Val Ser Pro Thr Phe Gln Asp LeuLeu Asn Arg Thr Thr 405 410 415 Ala Gly Gln Pro Thr Gly Trp Tyr Lys AspLeu Arg His Tyr Tyr Tyr 420 425 430 Arg Ala Arg Trp Glu Leu Tyr Asp ArgSer Arg Asp Pro His Glu Thr 435 440 445 Gln Asn Leu Ala Thr Asp Pro ArgPhe Ala Gln Leu Leu Glu Met Leu 450 455 460 Arg Asp Gln Leu Ala Lys TrpGln Trp Glu Thr His Asp Pro Trp Val 465 470 475 480 Cys Ala Pro Asp GlyVal Leu Glu Glu Lys Leu Ser Pro Gln Cys Gln 485 490 495 Pro Leu His AsnGlu Leu 500 25 amino acids amino acid single linear peptide not provided3 Arg Pro Arg Asn Ala Leu Leu Leu Leu Ala Asp Asp Gly Gly Phe Glu 1 5 1015 Ser Gly Ala Tyr Xaa Asn Ser Ala Ile 20 25

1. An isolated nucleic acid molecule comprising a sequence ofnucleotides which encodes or is complementary to a sequence whichencodes a mammalian sulphamidase or fragment or derivative thereof. 2.The isolated nucleic acid molecule according to claim 1 wherein thenucleotides are deoxyribonucleotides.
 3. The isolated nucleic acidmolecule according to claim 2 which said molecule is cDNA.
 4. Theisolated nucleic acid molecule according to claim 2 wherein saidmolecule is a genomic DNA molecule.
 5. The isolated nucleic acidaccording to any one of claims 1 to 4 wherein the mammal is a human. 6.The isolated nucleic acid according to claim 5 wherein the sulphamidaseis of liver, kidney or placenta origin.
 7. The isolated nucleic acidmolecule according to claim 3 or 4 wherein said molecule is carried by avector capable of replication in a eukaryotic cell and/or a prokaryoticcell.
 8. The isolated nucleic acid molecule according to claim 7 whereinthe vector is an expression vector.
 9. The isolated nucleic acidmolecule according to claim 1 having a nucleotide sequence substantiallyas set forth in SEQ ID NO: 1 or having at least 40% similarity to all orpart thereof.
 10. The isolated nucleic acid molecule according to claim9 wherein the percentage similarity is at least 60%.
 11. The isolatednucleic acid molecule according to claim 10 wherein the percentagehomology is at least 80%.
 12. The isolated nucleic acid moleculeaccording to claim 8 when expressed in eukaryotic cells.
 13. Theisolated nucleic acid molecule according to claim 1 when expressed inmammalian cells.
 14. A recombinant mammalian sulphamidase or fragment orderivative thereof.
 15. The recombinant mammalian sulphamidase accordingto claim 14 in substantially pure form.
 16. The recombinant mammaliansulphamidase according to claim 14 or 15 when expressed in mammalian,yeast or insect cells.
 17. The recombinant mammalian sulphamidaseaccording to claim 16 when expressed in mammalian cells.
 18. Therecombinant mammalian sulphamidase according to claim 17 having analtered glycosylation pattern compared to the naturally occurringmolecule.
 19. The recombinant mammalian sulphamidase according to claim18 being more highly glycosylated compared to the naturally occurringmolecule.
 20. The recombinant mammalian sulphamidase according to claim14 wherein the mammalian sulphamidase is of human origin.
 21. Therecombinant mammalian sulphamidase according to claim 14 when fused toanother proteinaceous molecule.
 22. The recombinant mammaliansulphamidase according to claim 21 wherein said other proteinaceousmolecule is an enzyme, reporter molecules purification site and/or asignal sequence.
 23. The recombinant mammalian sulphamidase according toclaim 14 having an amino acid sequence substantially as set forth in SEQID NO:2 or having at least 40% similarity to all or part thereof.
 24. Amethod for treating a patient suffering from sulphamidase deficiencysaid method comprising administering to said patient an effective amountof recombinant mammalian sulphamidase or an active fragment orderivative thereof.
 25. The method according to claim 24 wherein themammalian sulphamidase is of human origin.
 26. The method according toclaim 24 wherein the patient is suffering from mucopolysaccharidosistype IIIA.
 27. The method according to claim 24 or 25 wherein therecombinant sulphamidase is expressed in mammalian cells.
 28. The methodaccording to claim 27 wherein the recombinant sulphamidase comprises analtered glycosylation pattern compared to the naturally occurringenzyme.
 29. The method according to claim 23 wherein the sulphamidase ismore highly glycosylated than the naturally occurring molecule.
 30. Themethod according to any one of claim 24 to 28 wherein administration ofthe sulphamidase is by oral, intravenous, suppository, intraperitoneal,intramuscular, intranasal, intradermal or subcutaneous administration byinfusion or implantation or by gene therapy.
 31. The method according toclaim 30 wherein the method of administration is by intravenousinjection or by gene therapy.
 32. A pharmaceutical compositioncomprising recombinant mammalian sulphamidase or an active fragment orderivative thereof and one or more pharmaceutically acceptable carriersand/or diluents.
 33. The pharmaceutical composition according to claim32 wherein the mammalian sulphamidase is of human origin.
 34. Thepharmaceutical composition according to claim 32 or 33 when expressed ina mammalian cell.
 35. The pharmaceutical composition according to claim34 wherein the sulphamidase has an altered glycosylation patterncompared to the naturally occurring molecule.
 36. The pharmaceuticalcomposition according to claim 35 wherein the sulphamidase is morehighly glycosylated compared to the naturally occurring molecule.
 37. Apharmaceutical composition comprising recombinant mammalian sulphamidasewhen used in the method according to claim 24 .
 38. Use of recombinantmammalian sulphamidase or an active fragment or derivative thereof inthe manufacture of a medicament for the treatment of sulphamidasedeficiency in a patient.
 39. The use according to claim 38 wherein themammalian sulphamidase is of human origin.
 40. The use according toclaim 38 or 39 wherein the patient is suffering frommucopolysaccharidosis type IIIA.
 41. The use according to claim 40wherein the sulphamidase is expressed in mammalian cells.
 42. The useaccording to claim 41 wherein the sulphamidase has an alteredglycosylation pattern compared to the naturally occurring molecule. 43.The use according to claim 42 wherein the sulphamidase is more highlyglycosylated compared to the naturally occurring molecule.
 44. A nucleicacid molecule comprising a sequence of nucleotides encoding orcomplementary to a sequence encoding a polypeptide capable ofhydrolysing the sulphate ester bond in 2-sulphaminoglucosamine residuesand wherein said nucleotide sequence is capable of hybridising under lowstringency conditions to the nucleotide sequence set fort in FIG. 2 (SEQID NO:1).
 45. A polypeptide comprising a sequence of amino acidscorresponding to the amino sequence set forth in FIG. 2 (SEQ ID NO:2) orhaving at least 40% similarity thereto or encoded by the nucleotidesequence set forth in FIG. 2 (SEQ ID NO: 1) or a nucleotide sequencecapable of hybridising to SEQ ID NO:1 under low stringent conditions.46. A non-naturally occurring chemically modified mammalian sulphamidasewherein said sulphamidase is characterised by an increased circulatoryhalf-life and/or increase penetrability of cartilage or the blood brainbarrier.
 47. A chemically modified sulphamidase according to claim 46wherein said enzyme, undergoing interaction with polylysine orpolyethyleneglycol.